Stretchable ink composition

ABSTRACT

A stretchable ink composition comprising a polyester; a polyurethane elastomer; water; a co-solvent; an optional surfactant; and an optional colorant.

RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application Ser.No. 61/849,815 filed Feb. 6, 2013, which is hereby incorporated byreference herein in its entirety.

Commonly assigned U.S. patent application Ser. No. 13/957,185, entitled“A Solventless Radiation Curable Stretchable Ink Composition”, with thenamed inventors Cameron Derry, Yiliang Wu, Naveen Chopra, and Peter G.Odell, filed concurrently herewith, is hereby incorporated by referenceherein in its entirety.

Commonly assigned U.S. patent application Ser. No. 13/957,374, entitled“Stretchable Ink Composition”, with the named inventors Yiliang Wu andCameron Derry, filed concurrently herewith, is hereby incorporated byreference herein in its entirety.

BACKGROUND

The present embodiments relate to ink compositions suitable for printingmarks or images on deformable substrates. In particular, disclosedherein is a stretchable water-based ink composition. These inkcompositions can be used for ink jet printing.

Printing marks or images on deformable substrates is desirable for manyapplications, such as flexible medical devices, including surgical toolsand implantable medical devices, robot skins, textiles (e.g., forstretchable swimming suits), rubber products such as tires, tubes, andcables, and the like. Consumable products based on rubbers and sometextiles are also stretchable. Because of the highly deformablecharacteristic of the substrate, a stretchable ink is desired forprinting on such substrates to achieve excellent image quality, imagerobustness, and image longevity.

Previous work by the inventors includes a stretchable ink compositionwhich comprises water, a colorant, a surfactant, and a fluoroelastomer,as disclosed in U.S. patent application Ser. No. 13/182,579 to Wu etal., filed on Jul. 14, 2011, which is hereby incorporated by referenceherein in its entirety.

U.S. patent application Ser. No. 13/495,915, which is herebyincorporated by reference herein in its entirety, of Wu et al.,describes in the Abstract thereof an ink composition suitable for inkjet printing, including printing on deformable substrates. Inembodiments, the stretchable ink composition is based on an aqueous inkformulation comprising an emulsion of a polyurethane elastomer incombination with colorant dispersions, and surfactants.

Water-based latex inks have been proposed. Certain water-based latexinks comprise water, water-miscible co-solvent, latex particles, andcolorant such as pigment particles. For example, certain wide-format inkjet printers employ latex inks. The inks are cured inside the printerusing radiant heat and forced air to coalesce latex particles into afilm that encapsulates the pigments and bonds to print media. Whilerobust images can be formed on normal paper or coated paper with suchinks, there remains a need for a latex ink that can be successfully usedon deformable materials which are used for many applications such asflexible medical devices, robot skins, textiles (e.g. for stretchableswimming suits), rubber products including tires, tubes, and cables. Dueto the highly deformable characteristic of the substrate materials, astretchable ink, preferably with pigment colorants, is desirable thatcan print on deformable substrates while achieving excellent imagerobustness and image longevity. Current latex inks are not stretchable.Further, current latex inks are generally based on acrylate resin whichcan be cost prohibitive.

While known compositions and processes are suitable for their intendedpurposes, a need remains for improved ink compositions with certaincharacteristics. Specifically, a need remains for ink compositionssuitable for printing on deformable or stretchable substrates.Additionally, a need remains for stretchable inks that form robustimages which can be stretched and relaxed for a high number of cycles.There is also a need for stretchable inks that have good colorstability. There is also a need for stretchable inks that exhibit goodresistance to environmental factors such as light, chemicals, water, andoxidizing gases, thus generating hydrophobic and water-resistant images.There further remains a need for stretchable inks that are suitable forboth indoor and outdoor applications. There further remains a need forsuch inks can be applied digitally.

The appropriate components and process aspects of the each of theforegoing U.S. Patents and Patent Publications may be selected for thepresent disclosure in embodiments thereof. Further, throughout thisapplication, various publications, patents, and published patentapplications are referred to by an identifying citation. The disclosuresof the publications, patents, and published patent applicationsreferenced in this application are hereby incorporated by reference intothe present disclosure to more fully describe the state of the art towhich this invention pertains.

SUMMARY

Described is a stretchable ink composition comprising a polyester; apolyurethane elastomer; water; a co-solvent; an optional surfactant; andan optional colorant.

Also described is a patterned article comprising a deformable substrate;an image printed on the deformable substrate, the image being formedfrom a stretchable ink comprising a polyester; a polyurethane elastomer;water; a co-solvent; an optional surfactant; and an optional colorant.

DETAILED DESCRIPTION

A stretchable ink composition is provided comprising a polyester; apolyurethane elastomer; water; a co-solvent; an optional surfactant; andan optional colorant.

In embodiments, the stretchable ink composition comprises an emulsion ofa polyester resin, an emulsion of a polyurethane elastomer, a pigmentdispersion, and surfactants. In other embodiments, the stretchable inkcomposition comprises a latex comprising the polyester resin, a latexcomprising the polyurethane elastomer, a pigment dispersion, andsurfactants. The stretchable ink composition can be ink jet printed ontovarious deformable substrates, such as for example, a stretchable latexrubber substrate, to provide an image having image longevity. Theprinted images exhibit superior performance on the deformablesubstrates, which are generally difficult to print upon.

In embodiments, the stretchable ink composition can be used to prepare apatterned article. In embodiments, a patterned article is providedcomprising a deformable substrate; an image printed on the deformablesubstrate, the image being formed from a stretchable ink comprising apolyester; a polyurethane elastomer; water; a co-solvent; an optionalsurfactant; and an optional colorant.

In embodiments, the stretchable ink herein has a low viscosity which iscompatible with inkjet printing methods. The printed stretchable inkprovided herein can form robust images on a variety of substrateincluding normal paper, coated photo paper, and rubber substrate.Moreover, in embodiments, images printed with the stretchable ink hereincan be stretched hundreds cycles without showing any crack andde-lamination, when printed on a deformable substrate, in embodiments, arubber substrate.

The stretchable ink compositions herein comprise polyester resin, whichis a low cost material for xerographic applications, in combination withpolyurethane elastomer. In certain embodiments, the stretchable ink is aradiation curable ink, in embodiments, an ultra-violet radiation curableink.

Polyester.

In embodiments, the stretchable ink composition herein is based on anaqueous formulation comprising an emulsion of polyester in combinationwith an emulsion of elastomer materials.

Any suitable or desired polyester can be used for the stretchable inkcompositions herein. In embodiments, the polyester can be a materialdescribed in U.S. Pat. Nos. 6,593,049 and 6,756,176, which are eachhereby incorporated by reference herein in their entireties. Suitableresins can also include a mixture of an amorphous polyester resin and acrystalline polyester resin as described in U.S. Pat. No. 6,830,860,which is hereby incorporated by reference herein in its entirety.

In embodiments, the resin can be a polyester resin formed by reacting adiol with a diacid in the presence of an optional catalyst. For forminga crystalline polyester, suitable organic diols include aliphatic diolshaving from about 2 to about 36 carbon atoms, such as 1,2-ethanediol,1,3-propanediol, 1,4-butanediol, 1,5-pentanediol,2,2-dimethylpropane-1,3-diol, 1,6-hexanediol, 1,7-heptanediol,1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, andthe like, including their structural isomers.

The aliphatic diol can be selected in any suitable or desired amount, inembodiments, from about 40 to about 60 mole percent, or from about 42 toabout 55 mole percent, or from about 45 to about 53 mole percent, and,in embodiments, a second diol can be selected in any suitable or desiredamount, in embodiments, from about 0 to about 10 mole percent, or fromabout 1 to about 4 mole percent of the resin.

Examples of organic diacids or diesters including vinyl diacids or vinyldiesters that can be selected for the preparation of the crystallineresins include oxalic acid, succinic acid, glutaric acid, adipic acid,suberic acid, azelaic acid, sebacic acid, fumaric acid, dimethylfumarate, dimethyl itaconate, cis-1,4-diacetoxy-2-butene, diethylfumarate, diethyl maleate, phthalic acid, isophthalic acid, terephthalicacid, naphthalene-2,6-dicarboxylic acid, naphthalene-2,7-dicarboxylicacid, cyclohexane dicarboxylic acid, malonic acid, mesaconic acid, adiester or anhydride thereof, and mixtures and combinations thereof.

The organic diacid can be selected in any suitable or desired amount, inembodiments, from about 40 to about 60 mole percent, or from about 42 toabout 52 mole percent, or from about 45 to about 50 mole percent, and inembodiments, a second diacid can be selected in any suitable or desiredamount, such as from about 0 to about 10 mole percent of the resin.

Polyester based crystalline resins include poly(ethylene-adipate),poly(propylene-adipate), poly(butylene-adipate),poly(pentylene-adipate), poly(hexylene-adipate), poly(octylene-adipate),poly(ethylene-succinate), poly(propylene-succinate),poly(butylene-succinate), poly(pentylene-succinate),poly(hexylene-succinate), poly(octylene-succinate),poly(ethylene-sebacate), poly(propylene-sebacate),poly(butylene-sebacate), poly(pentylene-sebacate),poly(hexylene-sebacate), poly(octylene-sebacate),poly(decylene-sebacate), poly(decylene-decanoate),poly(ethylene-decanoate), poly(ethylene-dodecanoate),poly(nonylene-sebacate), poly(nonylene-decanoate),copoly(ethylene-fumarate)-copoly(ethylene-sebacate),copoly(ethylene-fumarate)-copoly(ethylene-decanoate),copoly(ethylene-fumarate)-copoly(ethylene-dodecanoate),copoly(2,2-dimethylpropane-1,3-diol-decanoate)-copoly(nonylene-decanoate),poly(octylene-adipate).

Examples of diacid or diesters selected for the preparation of amorphouspolyesters include dicarboxylic acids or diesters such as terephthalicacid, phthalic acid, isophthalic acid, fumaric acid, trimellitic acid,dimethylfumarate, dimethylitaconate, cis-1,4-diacetoxy-2-butene, diethylfumarate, diethyl maleate, maleic acid, succinic acid, itaconic acid,succinic anhydride, dodecylsuccinic acid, dodecylsuccinic anhydride,glutaric acid, glutaric anhydride, adipic acid, pimelic acid, subericacid, azelaic acid, dodecanediacid, dimethyl terephthalate, diethylterephthalate, dimethylisophthalate, diethylisophthalate,dimethylphthalate, phthalic anhydride, diethylphthalate,dimethylsuccinate, dimethylfumarate, dimethylmaleate, dimethylglutarate,dimethyladipate, dimethyl dodecylsuccinate, and mixtures andcombinations thereof. The organic diacid or diester may be present inany suitable or desired amount, for example, in an amount from about 40to about 60 mole percent of the resin, or from about 42 to about 55 molepercent of the resin, or from about 45 to about 53 mole percent of theresin.

Examples of diols which can be utilized in generating the amorphouspolyester include 1,2-propanediol, 1,3-propanediol, 1,2-butanediol,1,3-butanediol, 1,4-butanediol, pentanediol, hexanediol,2,2-dimethylpropanediol, 2,2,3-trimethylhexanediol, heptanediol,dodecanediol, bis(hydroxyethyl)-bisphenol A,bis(2-hydroxypropyl)-bisphenol A, 1,4-cyclohexanedimethanol,1,3-cyclohexanedimethanol, xylenedimethanol, cyclohexanediol, diethyleneglycol, bis(2-hydroxyethyl) oxide, dipropylene glycol, dibutylene, andmixtures and combinations thereof. The amount of organic diol selectedcan vary, and may be selected in any suitable or desire amount, forexample, in an amount of from about 40 to about 60 mole percent of theresin, or from about 42 to about 55 mole percent of the resin, or fromabout 45 to about 53 mole percent of the resin.

Amorphous polyester resins include alkali sulfonated-polyester resins,branched alkali sulfonated-polyester resins, alkali sulfonated-polyimideresins, and branched alkali sulfonated-polyimide resins. Alkalisulfonated polyester resins include the metal or alkali salts ofcopoly(ethylene-terephthalate)-copoly(ethylene-5-sulfo-isophthalate),copoly(propylene-terephthalate)-copoly(propylene-5-sulfo-isophthalate),copoly(diethylene-terephthalate)-copoly(diethylene-5-sulfo-isophthalate),copoly(propylene-diethylene-terephthalate)-copoly(propylene-diethylene-5-sulfo-isophthalate),copoly(propylene-butylene-terephthalate)-copoly(propylene-butylene-5-sulfo-isophthalate),and copoly(propoxylated bisphenol-A-fumarate)-copoly(propoxylatedbisphenol A-5-sulfo-isophthalate).

In embodiments, polycondensation catalysts may be used in forming thepolyesters. Polycondensation catalysts which may be utilized for eitherthe crystalline or amorphous polyesters include tetraalkyl titanates,dialkyltin oxides such as dibutyltin oxide, tetraalkyltins such asdibutyltin dilaurate, and dialkyltin oxide hydroxides such as butyltinoxide hydroxide, aluminum alkoxides, alkyl zinc, dialkyl zinc, zincoxide, stannous oxide, and mixtures and combinations thereof. Suchcatalysts may be utilized in any suitable or desired amount, such asfrom about 0.01 mole percent to about 5 mole percent based on thestarting diacid or diester used to generate the polyester resin.

In embodiments, as noted above, an unsaturated, amorphous polyesterresin may be utilized as the polyester herein. Examples of such resinsinclude those disclosed in U.S. Pat. No. 6,063,827, the disclosure ofwhich is hereby incorporated by reference herein in its entirety.Exemplary unsaturated amorphous polyester resins include, but are notlimited to, poly(propoxylated bisphenol co-fumarate), poly(ethoxylatedbisphenol co-fumarate), poly(butyloxylated bisphenol co-fumarate),poly(co-propoxylated bisphenol co-ethoxylated bisphenol co-fumarate),poly(1,2-propylene fumarate), poly(propoxylated bisphenol co-maleate),poly(ethoxylated bisphenol co-maleate), poly(butyloxylated bisphenolco-maleate), poly(co-propoxylated bisphenol co-ethoxylated bisphenolco-maleate), poly(1,2-propylene maleate), poly(propoxylated bisphenolco-itaconate), poly(ethoxylated bisphenol co-itaconate),poly(butyloxylated bisphenol co-itaconate), poly(co-propoxylatedbisphenol co-ethoxylated bisphenol co-itaconate), poly(1,2-propyleneitaconate), and combinations thereof.

In embodiments, a suitable polyester resin may be a an amorphouspolyester such as a poly(propoxylated bisphenol A co-fumarate) resinhaving the formula

wherein m is an integer, in embodiments of from about 5 to about 1000,or from about 10 to about 500, or from about 15 to about 200.

An example of a linear propoxylated bisphenol A fumarate resin which maybe utilized as a latex resin is the resin available under the trade nameSPARII from Resana S/A Industrias Quimicas, Sao Paulo, Brazil. Otherpropoxylated bisphenol A fumarate resins that may be utilized and arecommercially available include GTUF and FPESL-2 from Kao Corporation,Japan, and EM181635 from Reichhold, Research Triangle Park, N.C.

Suitable crystalline resins which may be utilized, optionally incombination with an amorphous resin as described above, include thosedisclosed in U.S. Patent Publication 2006/0222991, the disclosure ofwhich is hereby incorporated by reference herein in its entirety. Inembodiments, a suitable crystalline resin may include a resin formed ofethylene glycol and a mixture of dodecanedioic acid and fumaric acidco-monomers of the formula

wherein b is an integer, in embodiments, of from about 5 to about 2,000and d is an integer, in embodiments, of from about 5 to about 2,000.

For example, in embodiments, a poly(propoxylated bisphenol Aco-fumarate) resin as described above may be combined with a crystallineresin to form a latex emulsion.

In embodiments, the resin may possess acid groups which, in embodiments,may be present at the terminal of the resin. Acid groups which may bepresent include carboxylic acid groups, and the like. The number ofcarboxylic acid groups may be controlled by adjusting the materialsutilized to form the resin and the reaction conditions.

In embodiments, the polyester resin may have an acid number from about 2mg KOH/g of resin to about 200 mg KOH/g of resin, or from about 5 mgKOH/g of resin to about 50 mg KOH/g of resin. The acid containing resinmay be dissolved in tetrahydrofuran solution. The acid number may bedetected by titration with KOH/methanol solution containingphenolphthalein as the indicator. The acid number may then be calculatedbased on the equivalent amount of KOH/methanol required to neutralizeall of the acid groups on the resin identified as the end point of thetitration.

In certain embodiments, the polyester has a glass transition temperature(Tg) of from about 30 to about 180° C., or from about 50 to about 150°C., or from about 60 to about 120° C. In a specific embodiment, thepolyester has a glass transition temperature of higher than about 30° C.

In certain embodiments, the polyester is provided in the form of anemulsion comprising the polyester. In other embodiments, the polyesteris provided in the form of a latex comprising the polyester. Inembodiments, the polyurethane is a polyurethane elastomer emulsion orpolyurethane latex; and the polyester is a polyester emulsion orpolyester latex.

In embodiments, the polyester emulsion or latex has a volume averageparticle size of from about 20 nanometers (nm) to about 1000 nm, or fromabout 20 to about 800 nm, or from about 50 to about 800 nm, or fromabout 50 to about 500 nm, or from about 50 to about 300 nm, or fromabout 100 to about 300 nanometers.

The characteristics of the polyester latex or emulsion, as well as thepolyurethane latex or emulsion described herein below, may be determinedby any suitable technique and apparatus. Volume average particlediameter may be measured by means of a measuring instrument such as aBeckman Coulter Multisizer 3, operated in accordance with themanufacturer's instructions.

In a specific embodiment, the polyester is a compound of the formula

wherein R is hydrogen or methyl, m is an integer of from about 2 toabout 10, and n is an integer of from about 2 to about 10.

In embodiments, the polyester may be present in any desired or effectiveamount, such from about 0.1 to about 25 percent, or from about 1 toabout 20 percent, or from about 2 to about 14 percent, by weight, basedon the total weight of the stretchable ink composition.

Polyurethane.

In embodiments, the stretchable ink composition herein is based on anaqueous formulation comprising an emulsion of polyester in combinationwith an emulsion of elastomer materials. An elastomer is defined by theCollins English Dictionary as any material, such as natural or syntheticrubber, that is able to resume its original shape when a deforming forceis removed.

A polyurethane elastomer, for the purposes of the present disclosure, isa polyurethane that behaves according to the above definition of anelastomer. Polyurethane is known to exhibit excellent chemical and waterresistance. Therefore, the present embodiments provide a stretchable inkthat is especially suitable for applications that are used outdoorsand/or involve exposure to moisture or water.

Polyurethane is a polymer comprising urethane groups of the formula

In embodiments, the polyurethane elastomer is the product of a polyol ofthe formulaHO-M-OH

wherein M is selected from the group consisting of polyester, polyether,polycaprolactones, polybutadiene, and mixtures thereof;

and an isocyanate of the formulaOCN—R₁—NCO

wherein R₁ is selected from the group consisting of an aromatic group,an aliphatic group, and mixtures thereof, and wherein R₁ has from about4 to about 24 carbon atoms;

with diol or diamine as the chain extender. An exemplary scheme forformation of polyurethane elastomer is illustrated below:

In embodiments, the M moiety in the polyol is selected from the groupconsisting of polyester, polyether, polycaprolactones, polybutadiene,and combinations thereof. In embodiments, the polyol has a molecularweight from about 300 to about 5000, or from about 500 to about 4000, orfrom about 600 to about 3000.

In embodiments, the polyurethane elastomer is a polyurethane elastomerwith a urethane linkage of the formulaOCN—R₂—NCO

wherein R₂ is selected from the group consisting of an aromatic group,an aliphatic group, and mixtures thereof, and wherein R₂ has from about4 to about 24 carbon atoms.

In embodiments, the polyurethane elastomer is a polyurethane elastomerwith a urea linkage of the formulaH₂N—R₃—NH₂

wherein R₃ is selected from the group consisting of an aromatic group,an aliphatic group, and mixtures thereof, and wherein R₂ has from about4 to about 24 carbon atoms.

In particular embodiments, the polyurethane is an aliphaticpolyurethane. In further embodiments, the polyurethane is a singlecomponent polyester based polyurethane elastomer. Such materials arecommercially available from Dow Chemical as Monothane™. In someembodiments, the polyurethane elastomer can be cured at roomtemperature. Polyurethane is a low cost material and thus use of thatelastomer in the present embodiments help reduce manufacturing costs.

In certain embodiments, the polyurethane has a glass transitiontemperature (Tg) of from about −70 to about 10° C., or from about −50 toabout 0° C., or from about −50 to about 5° C. In a specific embodiment,the polyurethane has a glass transition temperature of less than about0° C.

In certain embodiments, the polyurethane is provided in the form of anemulsion comprising a polyurethane.

In other embodiments, the polyurethane is provided in the form of alatex comprising the polyurethane.

In specific embodiments, the emulsion comprises nano-sized particles ofmaterials. In embodiments, the stretchable ink composition comprises anaqueous formulation comprising an emulsion or latex of polyurethaneelastomer materials wherein the elastomeric materials have an averageparticle size of from about 20 nanometers (nm) to about 1000 nm, or fromabout 20 to about 800 nm, or from about 50 to about 800 nm, or fromabout 50 to about 500 nm, or from about 50 to about 300 nm, or fromabout 100 to about 300 nanometers. For example, in such examples, theemulsion of elastomer materials comprises nano-sized particles having asize of from about 30 to about 1000 nm or from about 50 to about 600 nm.In such embodiments, the colorant can be dispersed in an emulsioncomprising particles having a size of from about 30 to about 1000 nm orfrom about 50 to about 600 nm or from about 50 to about 300 nm.

In embodiments, the polyurethane elastomer may be present in any desiredor effective amount, such from about 0.1 to about 25 percent, or fromabout 1 to about 20 percent, or from about 2 to about 14 percent, byweight, based on the total weight of the stretchable ink composition.

In embodiments, the polyurethane elastomer has a tensile strength of atleast about 0.5 MPa, at least about 1.0 MPa, at least about 3.0 MPa, atleast about 5.0 mPa, or no more than about 25 MPa, no more than about 20MPa, or no more than about 18 MPa, as measured by ASTM D412C, althoughthe tensile strength can be outside of these ranges. In certainembodiments, the polyurethane elastomer has a tensile strength of atleast 1.0 MPa to no more than 18 MPa.

In embodiments, the polyurethane elastomer has an elongation at break ofat least about 150%, at least about 200%, at least about 400%, or nomore than about 1100%, no more than about 1000%, or no more than about800%, as measured by ASTM D412C, although the elongation at break can beoutside of these ranges.

In embodiments, the polyurethane elastomer has a hardness (Shore A)value of at least about 20, at least about 30, at least about 40, or nomore than about 90, no more than about 85, or no more than about 80, asmeasured by ASTM 2240, although the hardness can be outside of theseranges.

The combination of the polyester having a high Tg and polyurethane witha low Tg enables a printed image with excellent stretchability and verygood document offset.

Colorant.

The stretchable ink composition herein may also contain a colorant. Anysuitable or desired colorant can be used in embodiments herein,including pigments, dyes, and mixtures and combinations thereof.

The colorant may be provided in the form of a colorant dispersion. Inembodiments, the colorant dispersion has an average particle size offrom about 20 to about 500 nanometers (nm), or from about 20 to about400 nm, or from about 30 to about 300 nm. In embodiments, the colorantis selected from the group consisting of dyes, pigments, andcombinations thereof, and optionally, the colorant is a dispersioncomprising a colorant, an optional surfactant, and an optionaldispersant.

In embodiments, with suitable surfactants, the polyester emulsion,polyurethane emulsion, or combination thereof, can be mixed togetherwith a colorant dispersion without forming any agglomerates. As aresult, the colorant is homogenously dispersed throughout thepolyurethane matrix. The viscosity of the mixture can subsequently beadjusted for inkjet printing. After being printed on a deformablesubstrate and dried, the ink composition forms robust images that couldbe stretched up to 150% for thousands of cycles. In further embodiments,the images can be stretched up to 300% for hundreds of cycles or up to500% for hundreds of cycles.

As noted, any suitable or desired colorant can be selected inembodiments herein. The colorant can be a dye, a pigment, or a mixturethereof. Examples of suitable dyes include anionic dyes, cationic dyes,nonionic dyes, zwitterionic dyes, and the like. Specific examples ofsuitable dyes include Food dyes such as Food Black No. 1, Food Black No.2, Food Red No. 40, Food Blue No. 1, Food Yellow No. 7, and the like, FD& C dyes, Acid Black dyes (No. 1, 7, 9, 24, 26, 48, 52, 58, 60, 61, 63,92, 107, 109, 118, 119, 131, 140, 155, 156, 172, 194, and the like),Acid Red dyes (No. 1, 8, 32, 35, 37, 52, 57, 92, 115, 119, 154, 249,254, 256, and the like), Acid Blue dyes (No. 1, 7, 9, 25, 40, 45, 62,78, 80, 92, 102, 104, 113, 117, 127, 158, 175, 183, 193, 209, and thelike), Acid Yellow dyes (No. 3, 7, 17, 19, 23, 25, 29, 38, 42, 49, 59,61, 72, 73, 114, 128, 151, and the like), Direct Black dyes (No. 4, 14,17, 22, 27, 38, 51, 112, 117, 154, 168, and the like), Direct Blue dyes(No. 1, 6, 8, 14, 15, 25, 71, 76, 78, 80, 86, 90, 106, 108, 123, 163,165, 199, 226, and the like), Direct Red dyes (No. 1, 2, 16, 23, 24, 28,39, 62, 72, 236, and the like), Direct Yellow dyes (No. 4, 11, 12, 27,28, 33, 34, 39, 50, 58, 86, 100, 106, 107, 118, 127, 132, 142, 157, andthe like), Reactive Dyes, such as Reactive Red Dyes (No. 4, 31, 56, 180,and the like), Reactive Black dyes (No. 31 and the like), ReactiveYellow dyes (No. 37 and the like); anthraquinone dyes, monoazo dyes,disazo dyes, phthalocyanine derivatives, including variousphthalocyanine sulfonate salts, aza (18) annulenes, formazan coppercomplexes, triphenodioxazines, and the like; and the like, as well asmixtures thereof.

Examples of suitable pigments include black pigments, white pigments,cyan pigments, magenta pigments, yellow pigments, or the like. Further,pigments can be organic or inorganic particles. Suitable inorganicpigments include carbon black. However, other inorganic pigments may besuitable such as titanium oxide, cobalt blue (CoO—Al₂O₃), chrome yellow(PbCrO₄), and iron oxide. Suitable organic pigments include, forexample, azo pigments including diazo pigments and monoazo pigments,polycyclic pigments (e.g., phthalocyanine pigments such asphthalocyanine blues and phthalocyanine greens), perylene pigments,perinone pigments, anthraquinone pigments, quinacridone pigments,dioxazine pigments, thioindigo pigments, isoindolinone pigments,pyranthrone pigments, and quinophthalone pigments), insoluble dyechelates (e.g., basic dye type chelates and acidic dye type chelate),nitro pigments, nitroso pigments, anthanthrone pigments such as PR168,and the like. Representative examples of phthalocyanine blues and greensinclude copper phthalocyanine blue, copper phthalocyanine green, andderivatives thereof (Pigment Blue 15, Pigment Green 7, and Pigment Green36). Representative examples of quinacridones include Pigment Orange 48,Pigment Orange 49, Pigment Red 122, Pigment Red 192, Pigment Red 202,Pigment Red 206, Pigment Red 207, Pigment Red 209, Pigment Violet 19,and Pigment Violet 42. Representative examples of anthraquinones includePigment Red 43, Pigment Red 194, Pigment Red 177, Pigment Red 216 andPigment Red 226. Representative examples of perylenes include PigmentRed 123, Pigment Red 149, Pigment Red 179, Pigment Red 190, Pigment Red189 and Pigment Red 224. Representative examples of thioindigoidsinclude Pigment Red 86, Pigment Red 87, Pigment Red 88, Pigment Red 181,Pigment Red 198, Pigment Violet 36, and Pigment Violet 38.Representative examples of heterocyclic yellows include Pigment Yellow1, Pigment Yellow 3, Pigment Yellow 12, Pigment Yellow 13, PigmentYellow 14, Pigment Yellow 17, Pigment Yellow 65, Pigment Yellow 73,Pigment Yellow 74, Pigment Yellow 90, Pigment Yellow 110, Pigment Yellow117, Pigment Yellow 120, Pigment Yellow 128, Pigment Yellow 138, PigmentYellow 150, Pigment Yellow 151, Pigment Yellow 155, and Pigment Yellow213. Such pigments are commercially available in either powder or presscake form from a number of sources including, BASF Corporation,Engelhard Corporation, and Sun Chemical Corporation. Examples of blackpigments that may be used include carbon pigments. The carbon pigmentcan be almost any commercially available carbon pigment that providesacceptable optical density and print characteristics. Carbon pigmentssuitable for use in the present system and method include, withoutlimitation, carbon black, graphite, vitreous carbon, charcoal, andcombinations thereof. Such carbon pigments can be manufactured by avariety of known methods, such as a channel method, a contact method, afurnace method, an acetylene method, or a thermal method, and arecommercially available from such vendors as Cabot Corporation, ColumbianChemicals Company, Evonik, and E.I. DuPont de Nemours and Company.Suitable carbon black pigments include, without limitation, Cabotpigments such as MONARCH 1400, MONARCH 1300, MONARCH 1100, MONARCH 1000,MONARCH 900, MONARCH 880, MONARCH 800, MONARCH 700, CAB-O-JET 200,CAB-O-JET 300, REGAL, BLACK PEARLS, ELFTEX, MOGUL, and VULCAN pigments;Columbian pigments such as RAVEN 5000, and RAVEN 3500; Evonik pigmentssuch as Color Black FW 200, FW 2, FW 2V, FW 1, FW18, FW S160, FW S170,Special Black 6, Special Black 5, Special Black 4A, Special Black 4,PRINTEX U, PRINTEX 140U, PRINTEX V, and PRINTEX 140V. The above list ofpigments includes unmodified pigment particulates, small moleculeattached pigment particulates, and polymer-dispersed pigmentparticulates. Other pigments can also be selected, as well as mixturesthereof. The pigment particle size is desired to be as small as possibleto enable a stable colloidal suspension of the particles in the liquidvehicle and to prevent clogging of the ink channels when the ink is usedin a thermal ink jet printer or a piezoelectric ink jet printer.

The colorant can be present in the stretchable ink composition in anydesired or effective amount, in embodiments, the colorant can be presentin an amount of from about 0.05 to about 15 percent, or from about 0.1to about 10 percent, or from about 1 to about 5 percent by weight, basedon the total weight of the stretchable ink composition.

Vehicle.

The stretchable ink composition herein comprises an liquid ink vehicle,in embodiments, an aqueous ink vehicle. Any suitable or desired materialcan be selected for the ink vehicle. The liquid vehicle can consistsolely of water, or it can comprise a mixture of water and a watersoluble or water miscible organic component, referred to as aco-solvent, humectant, or the like (hereinafter co-solvent) such asalcohols and alcohol derivatives, including aliphatic alcohols, aromaticalcohols, dials, glycol ethers, polyglycol ethers, long chain alcohols,primary aliphatic alcohols, secondary aliphatic alcohols, 1,2-alcohols,1,3-alcohols, 1,5-alcohols, ethylene glycol alkyl ethers, propyleneglycol alkyl ethers, methoxylated glycerol, ethoxylated glycerol, higherhomologues of polyethylene glycol alkyl ethers, and the like, withspecific examples including ethylene glycol, propylene glycol,diethylene glycols, glycerine, dipropylene glycols, polyethyleneglycols, polypropylene glycols, trimethylolpropane, 1,5-pentanediol,2-methyl-1,3-propanediol, 2-ethyl-2-hydroxymethyl-1,3-propanediol,3-methoxybutanol, 3-methyl-1,5-pentanediol, 1,3-propanediol,1,4-butanediol, 2,4-heptanediol, and the like; also suitable are amides,ethers, urea, substituted ureas such as thiourea, ethylene urea,alkylurea, alkylthiourea, dialkylurea, and dialkylthiourea, carboxylicacids and their salts, such as 2-methylpentanoic acid,2-ethyl-3-propylacrylic acid, 2-ethyl-hexanoic acid, 3-ethoxyproponic,acid, and the like, esters, organosulfides, organosulfoxides, sulfones(such as sulfolane), carbitol, butyl carbitol, cellusolve, ethers,tripropylene glycol monomethyl ether, ether derivatives, hydroxyethers,amino alcohols, ketones, N-methylpyrrolidinone, 2-pyrrolidinone,cyclohexylpyrrolidone, amides, sulfoxides, lactones, polyelectrolytes,methyl sulfonylethanol, imidazole, 1,3-dimethyl-2-imidazolidinone,betaine, sugars, such as 1-deoxy-D-galactitol, mannitol, inositol, andthe like, substituted and unsubstituted formamides, substituted andunsubstituted acetamides, and other water soluble or water misciblematerials, as well as mixtures thereof. In embodiments, the co-solventis selected from the group consisting of ethylene glycol,N-methylpyrrolidone, methoxylated glycerol, ethoxylated glycerol, andmixtures thereof. When mixtures of water and water soluble or miscibleorganic liquids are selected as the liquid vehicle, the water to organicratio ranges can be any suitable or desired ration, in embodiments fromabout 100:0 to about 30:70, or from about 97:3 to about 40:60, or fromabout 95:5 to about 60:40. The non-water component of the liquid vehiclegenerally serves as a humectant or co-solvent which has a boiling pointhigher than that of water (100° C.). The organic component of the inkvehicle can also serve to modify ink surface tension, modify inkviscosity, dissolve or disperse the colorant, and/or affect the dryingcharacteristics of the ink.

The liquid vehicle can be provided in any suitable or desired amount. Inembodiments, the liquid vehicle is present in the stretchable incomposition in an amount of from about 70 to about 99.9 percent, or fromabout 80 to about 99.5 percent, or from about 90 to about 99 percent, byweight, based on the total weight of the stretchable ink composition.

Surfactant.

The inks disclosed may also contain a surfactant. Any surfactant thatforms an emulsion of the polyurethane elastomer in the ink can beemployed. Examples of suitable surfactants include ionic surfactants,anionic surfactants, cationic surfactants, nonionic surfactants,zwitterionic surfactants, and the like, as well as mixtures thereof.Examples of suitable surfactants include alkyl polyethylene oxides,alkyl phenyl polyethylene oxides, polyethylene oxide block copolymers,acetylenic polyethylene oxides, polyethylene oxide (di)esters,polyethylene oxide amines, protonated polyethylene oxide amines,protonated polyethylene oxide amides, dimethicone copolyols, substitutedamine oxides, and the like, with specific examples including primary,secondary, and tertiary amine salt compounds such as hydrochloric acidsalts, acetic acid salts of laurylamine, coconut amine, stearylamine,rosin amine; quaternary ammonium salt type compounds such aslauryltrimethylammonium chloride, cetyltrimethylammonium chloride,benzyltributylammonium chloride, benzalkonium chloride, etc.; pyridiniumsalty type compounds such as cetylpyridinium chloride, cetylpyridiniumbromide, etc.; nonionic surfactant such as polyoxyethylene alkyl ethers,polyoxyethylene alkyl esters, acetylene alcohols, acetylene glycols; andother surfactants such as 2-heptadecenyl-hydroxyethylimidazoline,dihydroxyethylstearylamine, stearyldimethylbetaine, andlauryldihydroxyethylbetaine; fluorosurfactants; and the like, as well asmixtures thereof. Additional examples of nonionic surfactants includepolyacrylic acid, methalose, methyl cellulose, ethyl cellulose, propylcellulose, hydroxy ethyl cellulose, carboxy methyl cellulose,polyoxyethylene cetyl ether, polyoxyethylene lauryl ether,polyoxyethylene octyl ether, polyoxyethylene octylphenyl ether,polyoxyethylene oleyl ether, polyoxyethylene sorbitan monolaurote,polyoxyethylene stearyl ether, polyoxyethylene nonylphenyl ether,dialkylphenoxy poly(ethyleneoxy) ethanol, available from Rhone-Poulencas IGEPAL CA-210™ IGEPAL CA-520™, IGEPAL CA-720™, IGEPAL CO-890™, IGEPALC0-720™, IGEPAL C0-290™, IGEPAL CA-21O™, ANTAROX 890™, and ANTAROX 897™.Other examples of suitable nonionic surfactants include a blockcopolymer of polyethylene oxide and polypropylene oxide, including thosecommercially available as SYNPERONIC™ PE/F, such as SYNPERONIC™ PE/F108. Other examples of suitable anionic surfactants include sulfates andsulfonates, sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate, sodium dodecylnaphthalene sulfate, dialkyl benzenealkylsulfates and sulfonates, acids such as abitic acid available fromSigma-Aldrich, NEOGEN R™, NEOGEN SC™ available from Daiichi KogyoSeiyaku, combinations thereof, and the like. Other examples of suitableanionic surfactants include DOWFAX™ 2A1, an alkyldiphenyloxidedisulfonate from Dow Chemical Company, and/or TAYCA POWER BN2060 fromTayca Corporation (Japan), which are branched sodium dodecyl benzenesulfonates. Other examples of suitable cationic surfactants, which areusually positively charged, include alkylbenzyl dimethyl ammoniumchloride, dialkyl benzenealkyl ammonium chloride, lauryl trimethylammonium chloride, alkylbenzyl methyl ammonium chloride, alkyl benzyldimethyl ammonium bromide, benzalkonium chloride, cetyl pyridiniumbromide, C 12, C15, C17 trimethyl ammonium bromides, halide salts ofquaternized polyoxyethylalkylamines, dodecylbenzyl triethyl ammoniumchloride, MIRAPOL™ and ALKAQUAT™, available from Alkaril ChemicalCompany, SANIZOL™ (benzalkonium chloride), available from Kao Chemicals,and the like, as well as mixtures thereof. Mixtures of any two or moresurfactants can be used.

The optional surfactant can be present in any desired or effectiveamount, in embodiments, the surfactant is present in an amount of fromabout 0.01 to about 5 percent by weight, based on the total weight ofthe stretchable ink composition. It should be noted that the surfactantsare named as dispersants in some cases.

Crosslinking Agent.

The stretchable ink composition can further comprise crosslinkers. Inembodiments, the crosslinker is an organoamine, a dihydroxy aromaticcompound, isocyanate, a peroxide, a metal oxide, or the like, as well asmixtures thereof. Crosslinking can further enhance the physicalproperties of the images generated from the ink composition. Thecrosslinker can be present in any desired or effective amount, inembodiments from about 0.1 to about 20 percent, or from 5 to about 15percent, by weight, based on the total weight of the stretchable inkcomposition.

Additives.

The stretchable ink composition can further comprise additives. Optionaladditives that can be included in the stretchable ink compositionsinclude biocides, fungicides, pH controlling agents such as acids orbases, phosphate salts, carboxylates salts, sulfite salts, amine salts,buffer solutions, and the like, sequestering agents such as EDTA(ethylenediamine tetra acetic acid), viscosity modifiers, levelingagents, and the like, as well as mixtures thereof.

In embodiments, the stretchable ink composition is a low-viscositycomposition. The term “low-viscosity” is used in contrast toconventional high-viscosity inks such as screen printing inks, whichtend to have a viscosity of at least 1,000 centipoise (cps). In specificembodiments, the ink disclosed herein has a viscosity of no more thanabout 100 cps, no more than about 50 cps, or no more than about 20 cps,although the viscosity can be outside of these ranges. When used in inkjet printing applications, the ink compositions are generally of aviscosity suitable for use in said ink jet printing processes. Forexample, for thermal ink jet printing applications, at room temperature(i.e., about 25° C.), the ink viscosity is at least about 1 centipoise,no more than about 10 centipoise, no more than about 7 centipoise, or nomore than about 5 centipoise, although the viscosity can be outside ofthese ranges. For piezoelectric ink jet printing, at the jettingtemperature, the ink viscosity is at least about 2 centipoise, at leastabout 3 centipoise, no more than about 20 centipoise, no more than about15 centipoise, or no more than about 10 centipoise, although theviscosity can be outside of these ranges. The jetting temperature can beas low as about 20 to 25° C., and can be as high as about 90° C., ashigh as about 60° C., or as high as about 40° C., although the jettingtemperature can be outside of these ranges.

The stretchable ink compositions can be of any suitable or desired pH.For some embodiments, such as thermal ink jet printing processes, pHvalues can be at least about 2, at least about 3, at least about 5, upto about 11, up to about 10, or up to about 9, although the pH can beoutside of these ranges.

In embodiments, the stretchable ink compositions have a surface tensionof at least about 22 dynes per centimeter, at least about 25 dynes percentimeter, at least about 28 dynes per centimeter, no more than about40 dynes per centimeter, in another embodiment no more than about 38dynes per centimeter, and or no more than about 35 dynes per centimeter,although the surface tension can be outside of these ranges.

In embodiments, the stretchable ink compositions contain particulateshaving an average particle diameter of no larger than about 5micrometers (μm), no larger than about 2 μm, no larger than about 1 μm,or no larger than about 0.5 μm, although the particulate size can beoutside of these ranges. In specific embodiments, the polyurethaneelastomer is in an emulsion form in the ink, having an average particlediameter of no larger than about 2 μm, no larger than about 1 μm, or nolarger than about 0.5 μm, although the particulate size can be outsideof these ranges.

The ink compositions can be prepared by any suitable process, such as bysimple mixing of the ingredients. One process entails mixing all of theink ingredients together and filtering the mixture to obtain an ink.Inks can be prepared by mixing the ingredients, heating if desired, andfiltering, followed by adding any desired additional additives to themixture and mixing at room temperature with moderate shaking until ahomogeneous mixture is obtained, in embodiments from about 5 to about 10minutes. Alternatively, the optional ink additives can be mixed with theother ink ingredients during the ink preparation process, which takesplace according to any desired procedure, such as by mixing all theingredients, heating if desired, and filtering.

In a specific embodiment, the inks are prepared as follows: 1)preparation of an emulsion of the polyester optionally stabilized with asurfactant; 2) preparation of an emulsion of the polyurethane elastomeroptionally stabilized with a surfactant; 3) preparation of a dispersionof a colorant optionally stabilized with a surfactant; 4) mixing of thepolyester emulsion and the polyurethane elastomer emulsion with thecolorant dispersion; 5) optional filtering of the mixture; 6) additionof other additives such as co-solvents; and 7) optional filtering of thecomposition. In specific embodiments, different surfactants are selectedprovided that they are compatible with one another. In furtherembodiments, the selected surfactants are the same. The phrase“compatible” means that there is an absence of neutralization (pH orcharge) or reaction between them. The best indication of this is that nomajor or large agglomerates form after mixing the polyurethane elastomeremulsion and the colorant dispersion. This can be characterized byparticle size measurement. For example, the particle size of the mixtureis substantially the same as that before mixing.

Also disclosed herein is a process which comprises applying an inkcomposition as disclosed herein to a substrate in an imagewise pattern.

The ink compositions can be used in a process which entailsincorporating the ink composition into an ink jet printing apparatus andcausing droplets of the ink to be ejected in an imagewise pattern onto asubstrate. In a specific embodiment, the printing apparatus employs athermal ink jet process wherein the ink in the nozzles is selectivelyheated in an imagewise pattern, thereby causing droplets of the ink tobe ejected in imagewise pattern. In another embodiment, the printingapparatus employs an acoustic ink jet process wherein droplets of theink are caused to be ejected in imagewise pattern by acoustic beams. Inyet another embodiment, the printing apparatus employs a piezoelectricink jet process, wherein droplets of the ink are caused to be ejected inimagewise pattern by oscillations of piezoelectric vibrating elements.Any suitable substrate can be employed.

In a specific embodiment, the process entails printing the ink onto adeformable substrate, such as textile, rubber, rubber sheeting, plastic,plastic sheeting, coated paper, or the like. In some embodiments, thesubstrate is a stretchable substrate, such as textile or rubber sheets.In other embodiments, the substrate is a plastic which is deformable atan elevated temperature higher than the glass transition temperature ofthe plastic, for example, in the process of molding into 3-dimensionalobjects. When the ink disclosed herein is used, the imagewise patternwill not be damaged upon molding. The rubber sheets with the imagewisepattern can be used, for example, as wrap for a 3-D object.

In one embodiment, the inks disclosed herein can be printed on a rubbersubstrate, such as natural polyisoprene, polybutadiene rubber,chloroprene rubber, neoprene rubber, butyl rubber (copolymer ofisobutylene and isoprene), styrene-butadiene rubber, silicon rubber,nitrile rubber (which is a copolymer of butadiene and acrylonitrile),ethylene propylene rubber, ethylene propylene diene rubber,epichlorohydrin rubber, polyacrylic rubber, ethylene-vinyl acetate,polyether block amides, polysulfide rubber, chlorosulfonatedpolyethylene as Hypalon, or the like. In a specific embodiment, the inksdisclosed herein can be printed on a deformable substrate, inembodiments, silicon rubber, polyacrylic rubber, butyl rubber, orneoprene rubber substrate and the imaged substrate can be stretched inone axial direction (i.e., along the x-axis, as opposed to both thex-axis and the y-axis) to, in embodiments, at least 110%, at least 150%,at least 200%, or at least 500% of the length of its original dimension,in embodiments, at least about 50 times, at least about 100 times, or atleast about 500 times, without exhibiting visible cracks ordelamination. In embodiments, the stretchable ink has the characteristicthat an image printed with the stretchable ink composition can bestretched in one axial direction to up to at least 110% along the lengthof its original dimension without exhibiting any visible cracks ordelamination to the naked human eye; or has the characteristic that animage printed with the stretchable ink composition can be stretched inone axial direction to from about 110% to about 500% along the length ofits original dimension without exhibiting any visible cracks ordelamination to the naked human eye.

In embodiments, images generated with the stretchable inks herein arehighly water-resistant. In one embodiment, images generated with theinks exhibit a water droplet contact angle of at least about 80°, atleast about 90°, or at least about 95°, although the contact angle canbe outside of these ranges. The water-resistant characteristic rendersthe ink disclosed herein suitable for outdoor applications or printingon water-related products such vehicle wrap, swimming suits, and thelike.

In a specific embodiment, the images generated with the stretchable inksdisclosed herein have a good chemical resistance. For example, they canexhibit good to excellent resistance toward alcohols, acetic acid,acetamide, allyl bromide, allyl chloride, benzoyl chloride, ethers,esters, hydrocarbons, blood, salt solutions, and the like.

In embodiments, images generated with the stretchable inks disclosedherein have a tensile strength of at least about 1.0 MPa, at least about3 MPa, at least about 4 MPa, at least about 8 MPa, no more than about 25MPa, no more than about 20 MPa, or no more than about 18 MPa, asmeasured by ASTM D412C, although the tensile strength can be outside ofthese ranges.

In embodiments, images generated with the stretchable inks disclosedherein have an elongation at break of at least about 150%, at leastabout 200%, at least about 400%, no more than about 1000%, no more thanabout 800%, or no more than about 700%, as measured by ASTM 0412C,although the elongation at break can be outside of these ranges.Generally, the images have a larger elongation at break than that of thedeformable substrate.

In embodiments, images generated with the stretchable inks disclosedherein have a hardness (Shore A) value of at least about 20, at leastabout 30, at least about 40, no more than about 100, no more than about90, or no more than about 85, as measured by ASTM 2240, although thehardness can be outside of these ranges.

In embodiments, images generated with the stretchable inks disclosedherein form a continuous layer on the substrate. Therefore, the imageswill have a small color difference with or without stretching. This isin contrast to some conventional stretchable images that are composed ofa dots array. Images based on a discontinuous dots array have poor imagequality, especially upon stretching, for example, the color density willdecrease dramatically. In embodiments, the images generated with thestretchable ink composition herein has a color difference (ΔE) less than5.0, or less than 3.5, or less than 2.0, or less than 1.0, whenstretched in one axial direction to about 150%. It is generally knownthat human eyes cannot differentiate the colors with color difference(ΔE 2000) values of <3.0. Color difference (ΔE 2000) values of >6.0 areconsidered a very obvious color difference.

In embodiments, images generated with the stretchable inks disclosedherein have an excellent adhesion on various substrates prior to orafter stretching.

In embodiments, a patterned article herein comprises a deformablesubstrate; an image printed on the deformable substrate, the image beingformed from a stretchable ink comprising a polyester; a polyurethaneelastomer; water; a co-solvent; an optional surfactant; and an optionalcolorant. In a specific embodiment, the printed image can be stretchedalong one axis to at least 110% of the length of its original dimensionwithout exhibiting visible cracks or delamination from the deformablesubstrate. In another embodiment, the image printed with the stretchableink composition has a color difference less than 3.0 when stretched inone axial direction to about 150% relative to a non-stretched printedimage.

EXAMPLES

The following Examples are being submitted to further define variousspecies of the present disclosure. These Examples are intended to beillustrative only and are not intended to limit the scope of the presentdisclosure. Also, parts and percentages are by weight unless otherwiseindicated.

Example 1

Latex inks having two resin components were formulated and printed onthree different substrates: normal paper, coated paper, and rubbersubstrate. The resultant images were characterized for their imagerobustness.

Polyester of the Formula

wherein R is hydrogen or a methyl group, m is from about 2 to about 10,and n is from about 2 to about 10, having a glass transition temperatureof about 60° C. was used as the first resin.

A urethane elastomer emulsion, Precidium™ Aqua 90-A, an aliphaticpolyester based polyurethane from Quantum technical services (solidcontent 32 weight %), was used as the second resin, which has an averageparticle size of about 85 nanometers.

The polyester resin was first emulsified using 4-dodecylbenzenesulfonicacid (SDBS) surfactant, yield emulsion with an average particle sizeabout 50 nanometers. The emulsion was then mixed with the abovepolyurethane emulsion, pigment dispersion (Green 7, solid contents19.96%, surfactants SDBS), and co-solvents to minimize drying of the inkin the print nozzle.

The following table shows the ink formulations for Example Ink 1 (astretchable ink in accordance with the present disclosure) and aComparative Ink. As a comparison, an ink without the elastomer componentwas also prepared.

TABLE 1 Comparative Ink Example Ink 1 Polyurethane — 12.5% EmulsionPolyester 30% 12.5% Emulsion Ethylene Glycol 25%  25% Ethoxylated  6%  6% Glycerol Pigment  5%   5% Dispersion Water 34%  39%

The components were mixed very well for both the Comparative Ink and theExample Ink 1. Particle analysis showed no aggregation of the emulsionsupon mixing. The average particle sizes remained to be around 82nanometers. Both inks had a viscosity of about 3.5 cps.

Inks according to the formulas above were used to print images using aDMP-2800 (FujiFilm Dimatix, Santa Clara, Calif.) inkjet printer equippedwith 10 pL cartridges on normal paper, gloss paper (photo paper) andplasma cleaned latex rubber to characterize their adhesion and printquality. Print conditions such as waveform, voltage, and substratetemperature were all optimized for the best printing properties and keptconstant for each ink.

Comparative Ink.

When printed on normal paper, the image printed with the Comparative Inkhad good resolution and color density. Without any heat treatment theimage passed the tape test and could not be removed by rubbing with aneraser. When printed on gloss paper and latex rubber, the image againhad good resolution and color density. However, without heat treatmentthe image failed the tape test and was easily rubbed off. A secondsample was printed and thermally treated at 70° C. on a hot plate to drythe sample and to coalesce the latex particles. Even after heattreatment the image still failed both the tape test and rub test.

Example Ink 1.

When printed on normal paper, the image printed with the Example Ink 1of the present disclosure had good resolution and color density. Withoutheat treatment the image passed the rub test and tape test. When printedon gloss paper and latex rubber, the image again had good resolution andcolor density. Without heating the image failed the rub and tape test.After heating at 70° C. on a hot plate, the image passed both the rubtest and tape test.

Table 2 provides a summary of the adhesion based on rub and tape tests.

3M™ Scotch® tape was used for tape test. The tape was placed on top ofthe image with a 20 gram weight load, then the tape was removed gently.The percentage of an image that was removed by the tape was examined. 0%indicates an excellent adhesion, less than 5% is considered as goodadhesion, while larger than 20% is defined as poor adhesion. A cottonswap was used for the rub test. The image was rubbed 30 times with thecotton swap and then examined under a microscope. No or little surfacedamage was considered as good adhesion.

TABLE 2 Polyester Resin (I) + Polyester Resin (I) Precidium Aqua 90-ANormal paper Good Good Gloss paper Poor Good Latex rubber Poor Good

The image formed on the rubber substrate with the ink of the presentdisclosure was subjected to hundreds stretching-relaxation cycle toabout 150% elongation. No cracks and de-lamination was observed afterstretching.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also thatvarious presently unforeseen or unanticipated alternatives,modifications, variations or improvements therein may be subsequentlymade by those skilled in the art which are also intended to beencompassed by the following claims. Unless specifically recited in aclaim, steps or components of claims should not be implied or importedfrom the specification or any other claims as to any particular order,number, position, size, shape, angle, color, or material.

The invention claimed is:
 1. A stretchable ink composition comprising: apolyester emulsion or latex, wherein the glass transition temperature ofthe polyester is from 30° C. to about 180° C.; a polyurethane elastomeremulsion or latex, wherein the glass transition temperature of thepolyurethane elastomer is from about −70° C. to about 10° C.; water; aco-solvent; an optional surfactant; and an optional colorant.
 2. Thestretchable ink of claim 1, wherein the polyester is a compound of theformula

wherein R is hydrogen or methyl, m is an integer of from about 2 toabout 10, and n is an integer of from about 2 to about
 10. 3. Thestretchable ink of claim 1, wherein the polyurethane emulsion or latexhas a volume average particle size of from about 20 to about 800nanometers; and wherein the polyester emulsion or latex has a volumeaverage particle size of from about 20 nanometers to about 800nanometers.
 4. The stretchable ink of claim 1, wherein the polyurethaneelastomer is a product of a polyol and an isocyanate with diol ordiamine as a chain extender; wherein the polyol is a compound of theformulaHO-M-OH wherein M is selected from the group consisting of polyester,polyether, polycaprolactones, polybutadiene, and mixtures thereof; andwherein the isocyanate is a compound of the formulaOCN—R₁—NCO wherein R₁ is selected from the group consisting of anaromatic group, an aliphatic group, and mixtures thereof, and wherein R₁has from about 4 to about 24 carbon atoms.
 5. The stretchable ink ofclaim 1, wherein the polyurethane elastomer is a polyurethane elastomerwith a urethane linkage of the formulaOCN—R₂—NCO wherein R₂ is selected from the group consisting of anaromatic group, an aliphatic group, and mixtures thereof, and wherein R₂has from about 4 to about 24 carbon atoms.
 6. The stretchable ink ofclaim 1, wherein the polyurethane elastomer is a polyurethane elastomerwith a urea linkage of the formulaH₂N—R₃—NH₂ wherein R₃ is selected from the group consisting of anaromatic group, an aliphatic group, and mixtures thereof, and wherein R₂has from about 4 to about 24 carbon atoms.
 7. The stretchable ink ofclaim 1, wherein the co-solvent is an alcohol or alcohol derivativeselected from the group consisting of aliphatic alcohols, aromaticalcohols, diols, glycol ethers, polyglycol ethers, primary aliphaticalcohols, secondary aliphatic alcohols, 1,2-alcohols, 1,3-alcohols,1,5-alcohols, ethylene glycol alkyl ethers, propylene glycol alkylethers, methoxylated glycerol, and ethoxylated glycerol.
 8. Thestretchable ink of claim 1, wherein the co-solvent is selected from thegroup consisting of ethylene glycol, N-methylpyrrolidone, methoxylatedglycerol, ethoxylated glycerol, and mixtures thereof.
 9. The stretchableink of claim 1, wherein the surfactant is selected from the groupconsisting of ionic surfactants, nonionic surfactants, zwitterionicsurfactants, and mixtures thereof.
 10. The stretchable ink of claim 1,wherein the colorant is selected from the group consisting of dyes,pigments, and combinations thereof; and optionally, wherein the colorantis a dispersion comprising a colorant, an optional surfactant, and anoptional dispersant.
 11. The stretchable ink of claim 1, wherein thepolyurethane elastomer has a tensile strength of at least 1.0 MPa to nomore than 18 MPa.
 12. The stretchable ink of claim 1, having thecharacteristic that an image printed with the stretchable inkcomposition can be stretched in one axial direction to up to at least110% along the length of its original dimension without exhibiting anyvisible cracks or delamination to the naked human eye; or having thecharacteristic that an image printed with the stretchable inkcomposition can be stretched in one axial direction to from about 110%to about 500% along the length of its original dimension withoutexhibiting any visible cracks or delamination to the naked human eye.13. The stretchable ink of claim 1, wherein the stretchable ink is aradiation curable ink.